August 29, 2008

Cytokinetics Announces Clinical Trials Data Relating to Ispinesib to Be Presented at the 2008 ASCO Breast Cancer Symposium

Cytokinetics, Incorporated (NASDAQ: CYTK) announced today that data from an ongoing Phase I/II clinical trial of ispinesib are scheduled to be presented as a poster presentation at the 2008 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium, to be held September 5-7, 2008 at the Hilton Washington in Washington, DC.

In June 2008, as part of a poster session at the ASCO Annual Meeting, Cytokinetics announced interim data from the Phase I portion of its ongoing Phase I/II clinical trial of ispinesib, a novel kinesin spindle protein (KSP) inhibitor, administered as monotherapy as a first-line treatment in chemotherapy-naive patients with locally advanced or metastatic breast cancer. The authors concluded that preliminary data suggest that ispinesib is well-tolerated when dosed on days 1 and 15 every 28 days at doses up to 12 mg/m2. Results from additional patients enrolled in the ongoing Phase I, dose-escalation portion of this clinical trial are scheduled to be presented the 2008 ASCO Breast Cancer Symposium.

Poster Presentation at ASCO Breast Cancer Symposium:

Abstract #192: "A Phase I-II Trial of Ispinesib, a Kinesin Spindle Protein (KSP) Inhibitor, Dosed Every Two Weeks in Patients (pts) with Locally Advanced (LA) or Metastatic Breast Cancer (MBC) Previously Untreated with Chemotherapy (CT) for Metastatic Disease or Recurrence." (Poster Presentation on Friday, September 5, 2008, during the General Poster Session, 5:30 pm - 6:45 pm Eastern Time). The poster will be found in the Exhibit Hall at poster board #A50 and presented by Henry Gomez, MD from Instituto Nacional de Enfermedades Neoplasicas (INEN) in Lima, Peru.

About Cytokinetics

Cytokinetics is a biopharmaceutical company focused on the discovery, development and commercialization of novel small molecule drugs that may address areas of significant unmet clinical needs. Cytokinetics' cardiovascular disease program is focused to cardiac myosin, a motor protein essential to cardiac muscle contraction. Cytokinetics' lead compound from this program, CK-1827452, a novel small molecule cardiac myosin activator, entered Phase II clinical trials for the treatment of heart failure in 2007. Under a strategic alliance established in 2006, Cytokinetics and Amgen Inc. are performing joint research focused on identifying and characterizing activators of cardiac myosin as back-up and follow-on potential drug candidates to CK-1827452. Amgen has obtained an option for an exclusive license to develop and commercialize CK-1827452, subject to Cytokinetics' development and commercial participation rights. Cytokinetics' cancer program is focused on mitotic kinesins, a family of motor proteins essential to cell division. Under a strategic alliance established in 2001, Cytokinetics and GlaxoSmithKline (GSK) are conducting research and development activities focused on the potential treatment of cancer. Cytokinetics is developing two novel drug candidates that have arisen from this program, ispinesib and SB-743921, each a novel inhibitor of kinesin spindle protein (KSP), a mitotic kinesin. Cytokinetics is sponsoring a Phase I/II clinical trial of ispinesib as monotherapy as a first-line treatment in chemotherapy-naive patients with locally advanced or metastatic breast cancer. In addition, Cytokinetics is conducting a Phase I/II trial of SB-743921 in patients with non-Hodgkin or Hodgkin lymphomas. GSK has obtained an option for the joint development and commercialization of ispinesib and SB-743921. Cytokinetics and GSK are conducting collaborative research activities directed to the mitotic kinesin centromere-associated protein E (CENP-E). GSK-923295, a CENP-E inhibitor, is being developed under the strategic alliance by GSK; GSK began a Phase I clinical trial with GSK-923295 in 2007. In April 2008, Cytokinetics announced the selection of a potential drug candidate directed towards skeletal muscle contractility which may be developed as a potential treatment for skeletal muscle weakness associated with neuromuscular diseases or other conditions. All of these drug candidates and potential drug candidates have arisen from Cytokinetics' research activities and are directed towards the cytoskeleton. The cytoskeleton is a complex biological infrastructure that plays a fundamental role within every human cell. Additional information about Cytokinetics can be obtained at

This press release contains forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995 (the "Act"). Cytokinetics disclaims any intent or obligation to update these forward-looking statements, and claims the protection of the Safe Harbor for forward-looking statements contained in the Act. Examples of such statements include, but are not limited to, statements relating to Cytokinetics' research and development programs, including planned presentations relating to clinical trial results, and the properties and potential benefits of Cytokinetics' drug candidates and potential drug candidates. Such statements are based on management's current expectations, but actual results may differ materially due to various risks and uncertainties, including, but not limited to, potential difficulties or delays in the development, testing, regulatory approval or production of Cytokinetics' drug candidates that could slow or prevent clinical development or product approval, including risks that current and past results of clinical trials or preclinical studies may not be indicative of future clinical trials results, patient enrollment for clinical trials may be difficult or delayed, Cytokinetics' drug candidates may have adverse side effects or inadequate therapeutic efficacy, the U.S. Food and Drug Administration or foreign regulatory agencies may delay or limit Cytokinetics' or its partners' ability to conduct clinical trials, and Cytokinetics may be unable to obtain or maintain patent or trade secret protection for its intellectual property; Cytokinetics may incur unanticipated research and development and other costs or be unable to obtain additional financing necessary to conduct development of its products; standards of care may change and others may introduce products or alternative therapies for the treatment of indications Cytokinetics' drug candidates and potential drug candidates may target; and risks and uncertainties relating to the timing and receipt of payments from Cytokinetics' partners, including milestones and royalties on future potential product sales under its collaboration agreements with such partners. For further information regarding these and other risks related to Cytokinetics' business, investors should consult Cytokinetics' filings with the Securities and Exchange Commission.

 Contacts:  Scott R. Jordan (Media) Director, Corporate Development (650) 624-3000  Christopher S. Keenan (Investors) Director, Investor Relations (650) 624-3000  

SOURCE: Cytokinetics, Inc.